I hope you can help me!
I have a N2R1D with 2 x 1TB drives configured as RAID1. I inherited it from my old company when it closed and it has all my old data, archived images, etc.... lots of precious things. Now I also use it at home for backups and photos etc. Never had any problems with it.

I just updated my macbook os to 10.10 (It was running too fast and needed slowing down ). Before I did this, I shifted loads of stuff from my Hard drive to the NAS to make space. Now i can't access the NAS because "THE VERSION OF THE SERVER YOU ARE TRYING TO CONNECT TO IS NOT SUPPORTED"

The NAS is running firmware 1.0.0_2403 from 2009, so clearly needs updating.
Questions:
1) Where can i find the updates? The links on the LG site http://www.lg.com/us/support-product/lg-N2R1D# don't work.
2) If I can find the updates, can I update and not disturb the data on the NAS discs as I really can't afford to lose it?

The updates on that page are working for me. But I don't think that helps much, the release notes of the latest firmware (10094, December 2013) show:
6) Mac OS X 10.7 (Lion) support

When you Google on OSX 10.10 samba problems, you'll find that OSX 10.10 dropped support for SMB2, in favor of SMB3. I guess that is the source of your problem. Maybe you can work-around with this FAQ:

MacStrategy wrote:Q. I'm having problems file sharing to a Windows computer/connecting to a Windows server. Is the new SMB2 protocol in Yosemite causing issues?
A. Probably. You can control which protocol is used to connect to file servers in the Finder > Go menu > Connect to Server… dialogue box by using:

cifs://server.name.or.ipaddress = SMB1

smb://server.name.or.ipaddress = SMB2

afp://server.name.or.ipaddress = AFP

as I really can't afford to lose it?

You should have backups. A NAS is not a magical box in which data is safe for eternity. It contains mechanical disks, and sensitive electronics, so it *will fail*, some day.

But updating from 2043 to the latest firmware doesn't work - the file isn't accepted. I guess i would need to use some intermediate versions?

You can control which protocol is used to connect to file servers in the Finder > Go menu > Connect to Server… dialogue box by using:

cifs://server.name.or.ipaddress = SMB1

smb://server.name.or.ipaddress = SMB2

afp://server.name.or.ipaddress = AFP

This looks hopeful, but I have tried

[*]smb://192.168.0.6 = SMB2

and then tried

[*]cifs://192.168.0.6 = SMB1

and I still get the same message when i try to access the drive.

Any other suggestions?

You should have backups. A NAS is not a magical box

Yes! My bad. The NAS was originally used as a back-up, but I have now started shifting things onto it for primary storage as my laptop HD filled up. I guess I have been relying on a level of safety from the RAID configuration - my understanding is that there are 2 copies of the data on 2 separate HD's - but you are right an independent back-up is the thing to do. If I can access the drive, I swear it's the first thing I'll do!